Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector

Felix Aharonian , Hiroki Akamatsu , Fumie Akimoto , Steven W. Allen , Lorella Angelini , Marc Audard , Hisamitsu Awaki , Magnus Axelsson , Aya Bamba , Marshall W. Bautz , Roger Blandford , Laura W. Brenneman , Gregory V. Brown , Esra Bulbul , Edward M. Cackett , Maria Chernyakova , Meng P. Chiao , Paolo S. Coppi , Elisa Costantini , Jelle de Plaa , Cor P. de Vries , Jan-Willem den Herder , Chris Done , Tadayasu Dotani , Ken Ebisawa , Megan E. Eckart , Teruaki Enoto , Yuichiro Ezoe , Andrew C. Fabian , Carlo Ferrigno , Adam R. Foster , Ryuichi Fujimoto , Yasushi Fukazawa , Akihiro Furuzawa , Massimiliano Galeazzi , Luigi C. Gallo , Poshak Gandhi , Margherita Giustini , Andrea Goldwurm (1, 2) , Liyi Gu , Matteo Guainazzi , Yoshito Haba , Kouichi Hagino , Kenji Hamaguchi , Ilana M. Harrus , Isamu Hatsukade , Katsuhiro Hayashi , Takayuki Hayashi , Kiyoshi Hayashida , Junko S. Hiraga , Ann Hornschemeier , Akio Hoshino , John P. Hughes , Yuto Ichinohe , Ryo Iizuka , Hajime Inoue , Yoshiyuki Inoue , Manabu Ishida , Kumi Ishikawa , Yoshitaka Ishisaki , Masachika Iwai , Jelle Kaastra , Tim Kallman , Tsuneyoshi Kamae , Jun Kataoka , Satoru Katsuda , Nobuyuki Kawai , Richard L. Kelley , Caroline A. Kilbourne , Takao Kitaguchi , Shunji Kitamoto , Tetsu Kitayama , Takayoshi Kohmura , Motohide Kokubun , Katsuji Koyama , Shu Koyama , Peter Kretschmar , Hans A. Krimm , Aya Kubota , Hideyo Kunieda , Philippe Laurent (1, 2) , Shiu-Hang Lee , Maurice A. Leutenegger , Olivier Limousin (2) , Michael Loewenstein , Knox S. Long , David Lumb , Greg Madejski , Yoshitomo Maeda , Daniel Maier (1, 2) , Kazuo Makishima , Maxim Markevitch , Hironori Matsumoto , Kyoko Matsushita , Dan Mccammon , Brian R. Mcnamara , Missagh Mehdipour , Eric D. Miller , Jon M. Miller , Shin Mineshige , Kazuhisa Mitsuda , Ikuyuki Mitsuishi , Takuya Miyazawa , Tsunefumi Mizuno , Hideyuki Mori , Koji Mori , Koji Mukai , Hiroshi Murakami , Richard F. Mushotzky , Takao Nakagawa , Hiroshi Nakajima , Takeshi Nakamori , Shinya Nakashima , Kazuhiro Nakazawa , Kumiko K. Nobukawa , Masayoshi Nobukawa , Hirofumi Noda , Hirokazu Odaka , Takaya Ohashi , Masanori Ohno , Takashi Okajima , Naomi Ota , Masanobu Ozaki , Frits Paerels , Stéphane Paltani , Robert Petre , Ciro Pinto , Frederick S. Porter , Katja Pottschmidt , Christopher S. Reynolds , Samar Safi-Harb , Shinya Saito , Kazuhiro Sakai , Toru Sasaki , Goro Sato , Kosuke Sato , Rie Sato , Makoto Sawada , Norbert Schartel , Peter J. Serlemtsos , Hiromi Seta , Megumi Shidatsu , Aurora Simionescu , Randall K. Smith , Yang Soong , Lukasz Stawarz , Yasuharu Sugawara , Satoshi Sugita , Andrew Szymkowiak , Hiroyasu Tajima , Hiromitsu Takahashi , Tadayuki Takahashi , Shin'Ichiro Takeda , Yoh Takei , Toru Tamagawa , Takayuki Tamura , Takaaki Tanaka , Yasuo Tanaka , Yasuyuki T. Tanaka , Makoto S. Tashiro , Yuzuru Tawara , Yukikatsu Terada , Yuichi Terashima , Francesco Tombesi , Hiroshi Tomida , Yohko Tsuboi , Masahiro Tsujimoto , Hiroshi Tsunemi , Takeshi Go Tsuru , Hiroyuki Uchida , Hideki Uchiyama , Yasunobu Uchiyama , Shutaro Ueda , Yoshihiro Ueda , Shin'Ichiro Uno , C. Megan Urry , Eugenio Ursino , Shin Watanabe , Norbert Werner , Dan R. Wilkins , Brian J. Williams , Shinya Yamada , Hiroya Yamaguchi , Kazutaka Yamaoka , Noriko Y. Yamasaki , Makoto Yamauchi , Shigeo Yamauchi , Tahir Yaqoob , Yoichi Yatsu , Daisuke Yonetoku , Irina Zhuravleva , Abderahmen Zoghbi , Yuusuke Uchida

1 APC (UMR_7164) - AstroParticule et Cosmologie
2 CEA - Commissariat à l'énergie atomique et aux énergies alternatives

We present the results from the Hitomi Soft Gamma-ray Detector (SGD) observation of the Crab nebula. The main part of SGD is a Compton camera, which in addition to being a spectrometer, is capable of measuring polarization of gamma-ray photons. The Crab nebula is one of the brightest X-ray/gamma-ray sources on the sky, and the only source from which polarized X-ray photons have been detected. SGD observed the Crab nebula during the initial test observation phase of Hitomi. We performed data analysis of the SGD observation, SGD background estimation, and SGD Monte Carlo simulations, and successfully detected polarized gamma-ray emission from the Crab nebula with only about 5 ks exposure time. The obtained polarization fraction of the phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1% ± 10.6%), and the polarization angle is |${110{^{\circ}_{.}}7}$| +|${13{^{\circ}_{.}}2}$|/−|${13{^{\circ}_{.}}0}$| in the energy range of 60–160 keV (the errors correspond to the 1 σ deviation). The confidence level of the polarization detection was 99.3%. The polarization angle measured by SGD is about one sigma deviation with the projected spin axis of the pulsar, |${124{^{\circ}_{.}}0}$| ± |${0{^{\circ}_{.}}1}$|⁠.

Mots clés: polarization; X-rays: individual (Crab); instrumentation: polarimeters

Domaines: Astrophysique [astro-ph]

Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Steven W. Allen, Lorella Angelini, et al.. Detection of polarized gamma-ray emission from the Crab nebula with the Hitomi Soft Gamma-ray Detector. Publ.Astron.Soc.Jap., 2018, 70 (6), pp.113. ⟨10.1093/pasj/psy118⟩. ⟨hal-01922038⟩